Fiber glass mat is made in many weights and sizes and can be used for a variety of applications. A general discussion of glass fiber technology is provided in "Fiber Glass" by J. Gilbert Mohr and William P. Row, Van Nostrand, Reinhold Co., New York 1978, which is hereby incorporated by reference. Fiber glass mats of the nonwoven type are generally known.
U.S. Pat. No. 4,145,371 by Tohyama et al discloses a flame-retardant textile fiber consisting of PVA and an amino resin. The amino resin is a condensation product of formaldehyde with melamine and other amino compounds selected from urea, dicyandiamide and benzogranamine. The use of phosphorous additives is suggested to enhance the flame-retardant characteristics of the fiber. The addition of dicyandiamide was found to improve the color fastness of the fiber.
It is known to use relatively large amounts of a phosphorus containing compound to produce a fire retardant condensate as taught by Goulding et al in U.S. Pat. No. 4,159,139. There a melamine-aldehyde is reacted with a relatively large amount of at least one oxyacid of phosphorous in a condensation reaction to form the fire retardant, the inorganic phosphorus compound being added in sufficient amounts that phosphorous is present in the resulting condensation product in the ratio of 0.4-1.7 moles of phosphorus for every mole of melamine.
U.S. Pat. Nos. 4,560,612 and 4,609,709 assigned to Owens-Corning Fiberglas relate to a binder composition containing a urea-formaldehyde resin, a styrene-butadiene latex copolymer and a fully methylated melamine-formaldehyde resin. The binder is applied to glass fiber mats used in the production of roofing felts. The utilization of a fully methylated resin provides improved moisture resistance over prior art binders.
U.S. Pat. No. 4,183,832 by Munier et la teaches a method of preparing a melamine formaldehyde resin that has an improved shelf-life and a low free formaldehyde content.
The resin is used to increase the tensile strength and suppleness of 100% glass fiber mats.
U.S. Pat. No. 4,960,826 assigned to Borden, Inc. discloses melamine-containing resole, resitol and resite compositions containing at least one phenolic compound, at least one aldehyde compound and at least one free melamine. The compositions are primarily used in applications where hard binders are required, as in engineered, shaped or molded glass fiber containing fabricated parts, e.g. using that invention, C-stage products can be resistant to punking or thermal shock.
In the manufacture of wet laid nonwoven mats containing a large proportion of glass fibers, typically used binders such as urea-formaldehyde resins or polyvinyl acetate, styrene butadiene rubber and acrylic copolymer latexes, will burn. Even polyvinyl chloride resin systems, if not high enough in chloride, will burn and may emit hydrogen chloride and heavy smoke.
It is an object of the present invention to make nonwoven fiber glass fire retardant mats that contain a binder with a very high nitrogen content which increases the fire retardancy of the mat.
It is also an object of the present invention to make fire retardant fiber glass nonwoven mats that do not require or contain additional flame retardants such as phosphates, other than catalytic amounts of phosphorus compounds, ammonium compounds, aluminum compounds or chlorinated compounds whether inorganic or organic.